Aggregate function

[Pawn371]

Hello.

Recently I'm using aggregate function (stats package) and I noticed that it produces different results by different syntax I use.

Two type of syntax I used are:

• aggregate(x~y, data, fun)

• aggregate(data[...], by=list(...), fun)

Is it possible that aggregate function produces different results? Or different syntax could produce same results?

For the first type of syntax I noticed that produce different result when I use cbind to define variables to aggregate.

Thanks.

[FJCC]

I do not see that behavior, as shown in the example below. Can you post an example?
By the way, aggregate is not part of the dplyr package, it is in the stats package.

set.seed(123)
DF <- data.frame(Name=sample(LETTERS[1:2],10,replace = TRUE),
                 Place=sample(LETTERS[3:4],10,replace = TRUE),
                 Value=rnorm(10))
aggregate(Value~Name+Place,data = DF,FUN = mean)
#>   Name Place      Value
#> 1    A     C  0.1142822
#> 2    B     C -0.0230071
#> 3    A     D  0.3572065
#> 4    B     D  0.4978505
aggregate(DF$Value,by=list(DF$Name,DF$Place),FUN=mean)
#>   Group.1 Group.2          x
#> 1       A       C  0.1142822
#> 2       B       C -0.0230071
#> 3       A       D  0.3572065
#> 4       B       D  0.4978505

^{Created on 2022-08-24 by the reprex package (v2.0.1)}